The method? Picking out a white ghost from a series of nine images. Kind of like a cute, less annoying Captcha. The problem? It’s a terrible way to prove you are a person. It took [Steven] only 30 minutes to write a program that uses simple thresholding, SURF keypoints and FLANN matching to find the ghost. In his tests, he’s found the ghost with 100% accuracy. He also muses that there is an even more efficient way to do it, he was just too lazy to do it.